The present invention relates to techniques for replacing equipment at a wellsite. More specifically, the invention relates to techniques for replacing equipment, such as blowout preventers (BOPs), strippers, and/or components thereof used, for example, in subsea applications.
Oilfield operations are typically performed to locate and gather valuable downhole fluids. Oil rigs are positioned at wellsites, and downhole tools, such as drilling tools, are deployed into the ground to reach subsurface reservoirs. Many oilfield operations occur in the sea, or ocean. Subsea oilfield operations typically require the wellhead and other wellsite equipment to be located on the seabed, while an oil platform or vessel may be located at the water's surface. The wellsite equipment located at the seabed may comprise equipment, such as blow out preventers (BOPs), strippers, control devices, supporting tubing injectors, tubing reels, wireline units, or other subsea equipment.
In sub-sea oil and gas operations, there is often a need for a pressure barrier for moving conveyances, such as a slickline or coiled tubing. The stripper may act as a seal, or pressure barrier, that the conveyance is run through. As the coiled tubing is fed through the stripper, the stripper may seal the outer surface of the coiled tubing, thereby preventing sea water from entering the well, and/or wellbore fluids from leaving the wellbore inadvertently. The BOP may act as a safety device designed to ‘seal in’ large pressure surges in the wellbore. The BOP may have rams that automatically shut thereby closing and sealing in the wellbore.
The subsea equipment may become damaged over the life of the drilling operations. In some cases, the subsea equipment may be repaired and/or replaced by subsea divers, and/or brought to the surface by the diver. Techniques for performing repairs and/or replacement of certain wellsite equipment are disclosed, for example, in U.S. Pat. Nos. 3,741,296; 6,484,808; 5,961,094; 6,012,528; and 6,113,061 and U.S. Publication Nos. 2008/0185153; 2008/0185152; and 2009/0152817, the entire contents of which are incorporated by reference.
Despite the development of techniques for replacing BOP and/or stripper components, there remains a need to provide advanced techniques for performing replacement operations.